DE102023113985A1 - Inspection of elevator systems based on position measurements - Google Patents

Abstract

A method for checking an elevator system with a rotatably mounted traction sheave comprises at least the following steps: operating the elevator system (10) according to a predefined operating sequence, wherein at least one movable element (12, 14, 16) of the elevator system (10) is moved by driving the traction sheave (18); detecting a plurality of position values (32) while the movable element (12, 14, 16) is moved, wherein the position values each represent a spatial position of the movable element (12, 14, 16); and determining at least one test parameter (40) on the basis of the plurality of position values, wherein the test parameter represents the driving ability of the traction sheave (18).

Description

The present invention relates to a method for checking elevator systems, in particular rope elevator systems.

Operators of elevator systems are obliged to regularly check operational safety. In particular, it must be checked regularly whether the elevator system meets the specification for which the elevator system is approved. In the case of a rope elevator, for example, it must be ensured that the elevator system can reliably move and hold the maximum transport weight in the elevator car without the support element slipping on the traction sheave, which is critical to safety. For this purpose, the so-called traction capacity is determined, which must be checked regularly in accordance with the relevant regulations, in particular the technical rules for operational safety (TRBS 1201-4).

The traction capability generally represents the slip resistance of one or more support elements (e.g. support ropes or straps) on the traction sheave. It can be determined using known methods by first loading the car with a nominal load plus an additional load for a safety margin. The loaded car is then moved by the traction sheave in various operating situations, preferably in a downward direction, and strongly decelerated in order to determine whether or not the support element slips.

Carrying out the test procedure described is very complex in practice, as defined test loads have to be loaded into the elevator and then removed again after the test has been completed and, if necessary, taken to the next test location. The test also requires several people who need special training, which increases the effort required for the test accordingly.

Against the background described, the object of the present invention is to provide a method of the type mentioned at the outset and a testing device for a rope elevator system, which allows a simpler and more reliable testing of the driving ability of elevator systems.

The object is achieved according to a first aspect by a method having the features of claim 1. The method comprises at least the following steps: operating the elevator system according to a predefined operating sequence, wherein at least one movable element of the elevator system is moved by driving the traction sheave; detecting a plurality of position values while the movable element is being moved, wherein the plurality of position values each represent a position of the movable element; and determining at least one test parameter on the basis of the plurality of position values. The test parameter represents the driving ability of the traction sheave.

The method is based on measuring position values of the moving element, which can be formed by the elevator car, for example. Position values offer the advantage over other measured variables that they can be recorded precisely and contactlessly using reliable sensor technology. A corresponding sensor can also be arranged at any position on the moving element. However, depending on the type of sensor used, certain boundary conditions may have to be met. For example, in the case of position sensors whose location capability is based on radio signals or magnetic fields, the arrangement can be limited to areas that provide as little electromagnetic shielding as possible for the position sensor. However, under this boundary condition, the sensor device in question can be arranged flexibly.

The position values can also be used advantageously to determine other measured variables, in particular the acceleration of the moving element. The acceleration can in turn be used directly to determine the driving ability, in particular using a predetermined calculation rule.

Embodiments of the invention are disclosed in the dependent claims, the description and the figures.

A position value of the movable element can be formed by a numerical value that represents the position along a predefined coordinate axis, e.g. an axis of a Cartesian coordinate system. The position values are preferably defined one-dimensionally along a vertical axis extending orthogonally to the ground. This makes it possible in particular to specify the position of a car within the elevator shaft. However, the position values can also be defined multi-dimensionally, e.g. as points in a Cartesian coordinate system.

The position values can generally be defined relative to any initial value. Calibration of the position measurement to absolute Position values are therefore not absolutely necessary. However, they can be useful in some cases, e.g. to further increase the reliability of the process.

According to one embodiment, the method includes determining whether the test parameter violates a predetermined test criterion. This step can be carried out by a person trained to check elevator systems, who evaluates the test parameter based on prior knowledge. However, the step, like determining the test parameter, is preferably carried out as a computer-implemented method step. For example, it can be determined with the aid of a computer whether the test parameter exceeds or falls below one or more safety-relevant threshold values.

According to one embodiment, the elevator system is formed by a cable elevator system. In this case, the movable element is usually formed by a first load element (e.g. the elevator car) which is connected to a second load element of the elevator system (e.g. a counterweight) via at least one support means. The support means is deflected and driven between the first load element and the second load element by means of a rotatably mounted traction sheave in order to move the first load element and the second load element simultaneously. During operation, the support means is deflected and driven between the first load element and the second load element by means of a rotatably mounted traction sheave in order to move the first load element and the second load element simultaneously. The support means wraps around the traction sheave at least partially along its circumference with a contact surface which is decisive for the static friction between the support means and the traction sheave. The maximum possible rope tension ratio at which slipping of the support means is just avoided defines the traction capability of the traction sheave. It therefore represents the boundary between static friction and sliding friction, at which slippage of the suspension element just does not occur and therefore allows safe operation of the elevator system.

A support means can generally be formed by a rope or a belt. Other types of rope-like connecting elements are also conceivable.

According to a further embodiment, a mass is determined for at least one section of the suspension element, which is used to determine the test parameter. For example, the proportional cable mass that is added to the effective total weight on one side of the cable of the traction sheave, e.g. the elevator car side, can be included in the determination of the test parameter. Taking the proportional suspension element mass into account makes it possible to determine the traction capability with greater accuracy at any point in the elevator shaft. The elevator car can also be located at any point in the elevator shaft, for example.

According to a further embodiment, the movable element is formed on a speed limiter or a shaft copy of the elevator system. These elements are generally easily accessible so that, for example, a mobile test or sensor device for carrying out the method can be selectively mounted there.

According to a further embodiment, the position values are recorded with at least one mobile sensor device. The sensor device is preferably arranged on the movable element. However, an arrangement on a stationary element of the elevator system is also conceivable. For example, the sensor device can be set up to optically record the position of the movable element.

To increase the test accuracy, the position values can be recorded by several sensor devices arranged on the elevator system. These can be of the same type or different, e.g. based on different sensor types. The position values can then be particularly reliably corrected for measurement errors, e.g. in the form of outliers. For example, the position values can be measured redundantly by different sensor types and the measurement inaccuracies of the individual sensor types can be compensated.

According to a further embodiment, the sensor device has a position sensor which determines the position of the movable element on the basis of coded radio signals received by the position sensor. For this purpose, the position sensor can be equipped with a suitable radio receiver which is tuned to receive the radio signals, in particular their frequency range. The received radio signals can be modulated in terms of frequency, phase and/or amplitude and in this way carry the coded information. Pulse modulation is also conceivable. The radio signals are preferably received by a global, satellite-based positioning system, e.g. the GPS system (Global Positioning System). In this way, the position can be determined flexibly and largely independently of the environment within the elevator system and its local sensors. However, a local positioning system is also conceivable. set, according to which the position is determined relative to one or more stationary signal transmitters on the elevator system. The evaluation of the signals preferably takes place in an evaluation unit integrated in the position sensor.

According to a further embodiment, the sensor device has a magnetic sensor. This measuring approach also offers advantages in terms of contactless measurement regardless of the ambient conditions prevailing in the elevator shaft, which can be characterized in particular by dust and mechanical parts. The magnet-based location of the movable element requires that the magnetic field in the movement range of the movable element changes in relation to the magnetic field orientation and/or the magnetic field strength. A local magnetic field is conceivable that is built up for the purpose of measurement by permanent or electromagnets suitably arranged on the elevator system. Preferably, however, the measurement is based predominantly or exclusively on the measurement of the earth's magnetic field. The magnetic sensor can be designed as a geomagnetic sensor, which means that the formation of artificial local magnetic fields can be dispensed with.

According to a further embodiment, the sensor device has an air pressure sensor. This can be designed in particular as a barometric pressure sensor. In this case, the position measurement can be based on the atmospheric air pressure, which varies depending on the height above the ground and can therefore be used to determine a vertical position above the elevator floor. This is particularly advantageous in the case of high elevator systems, such as those regularly found in high-rise buildings. Any shielding of the movable element within an elevator shaft is not critical in the case of position determination based on air pressure.

According to a further embodiment, the sensor device has an optical image sensor. This generates image data that represents at least the movable element and therefore enables the position of the movable element to be determined. For this purpose, methods of automatic image data processing are preferably used that are based on deterministic evaluation rules and/or statistical models, in particular machine learning.

By taking chronologically consecutive images of the moving element, position differences can be determined by repeatedly detecting the moving element in the image data, which can be used to determine speed values for the moving element. The speed values can in turn be converted into acceleration values, which can be used directly to determine the propulsion capability. The position values determined on the basis of image data do not have to be used directly to determine the propulsion capability, but can be used to check the plausibility of the position values determined, for example, by a GPS or air pressure sensor. For example, the image data can be used to determine whether the moving element has been moved and therefore a change in the measured position is plausible.

In principle, speed and acceleration values of the moving element can also be based on those position values recorded by one or more of the previously mentioned sensor types, i.e. not necessarily on the basis of image data.

Within the scope of the described method, one or more difference values can generally be formed, each of which represents a difference between two position values of the movable element recorded one after the other and which are used to check the driving ability. The difference values can initially be used to determine the speed and/or acceleration values of the movable element, taking into account the recording times recorded for the position values involved.

For improved position measurement based on image data, it can be provided that the image data contain at least one stationary element of the elevator system in addition to the movable element. This can be used as a reference point relative to the movable element in order to be able to better compensate for changes in perspective within the image data.

The test procedure can be extended by determining additional measured values for a measurand that differs from the position of the moving element. The additional measured values can advantageously be included in the determination of the test parameter in order to improve the accuracy.

As an example of another measurement value, an acoustic signal can be recorded on the elevator system while the moving element is being moved. In the case of a rope elevator system, the rope vibrations caused by the rope are typically recorded, which provide information about the traction capability of the traction sheave. The Test parameters can therefore also be determined depending on the acoustic signal.

Another example of a measured value that differs from the position or position difference is a current and/or voltage value of the drive motor. This provides information about a load state of the drive motor that is related to a dynamic change in the position of the traction sheave.

According to a further embodiment, the position values and/or other measured values that are related to the driveability of the elevator system are recorded using a mobile test device. The test device can be designed as a mobile and compact terminal. It can be carried like a smartphone or the like by a person responsible for the test and can be easily arranged on the elevator system to be tested. The test is particularly flexible in this way. A further advantage is that the mobile test device is moved while the position values and/or other measured values are being recorded, e.g. on the elevator car or another moving part.

In a further embodiment, the measured values for determining the test parameter are evaluated depending on reference measured values. These can be based, for example, on a learning operation of the elevator system. In addition or alternatively, reference measured values can be included on the basis of predetermined specification data of the elevator system. The specification data includes, for example, data provided by a manufacturer of the elevator system or a component of the elevator system (e.g. by a sensor manufacturer). The data contains information about an expected and operationally safe behavior of the underlying component. A comparison of the current measured data with the expected reference data can therefore indicate safety risks and be used for a reliable inspection of the elevator system.

The measured values can be compared with the reference values in various ways. Preferably, a predetermined mathematical relationship is formed between the current measured values and the reference values, for example a correlation function (e.g. in the form of a cross-correlation or convolution function). Additionally or alternatively, a statistical machine learning model can be used, which also forms mathematical relationships between the measured values, e.g. by applying kernel functions. However, simpler function types can also be used, e.g. a large number of threshold comparisons in a neural network or a regression model.

As mentioned at the beginning, the elevator system is operated according to a predefined operating sequence while the measured values are being recorded. On the one hand, this can be specified by a regular operating sequence programmed into the elevator system, for example an elevator ride between two levels. Additionally or alternatively, a safety operating sequence can be provided, in particular an emergency stop, in which the preferably empty elevator car is braked with maximum braking acceleration in the upward direction (travel in the direction away from the ground).

According to a further embodiment, the measured values are processed depending on predetermined tolerance ranges. For example, a subset of the measured values can be excluded from the determination of the test parameter or modified according to a predetermined filter function if the measured values of the subset violate an assigned tolerance range, i.e. exceed or fall below corresponding threshold values. The reliability of the method can be significantly increased in this way; on the one hand because outliers in the measured values cannot influence the test result; on the other hand because the test model does not have to be designed to compensate for outliers. Measured values contaminated with noise or other measurement uncertainties can therefore also be used to check the elevator system.

According to a further embodiment, the method can be carried out at least partially on a central server which receives the measured values via a data network and determines the test parameter.

In a further embodiment, the method is at least partially embodied by a computer program in the form of instructions which, when the program is executed by a computer, cause the computer to carry out the method according to one of the described embodiments. In particular, the test parameter can be determined by a computer program.

The computer program is preferably stored as application software, in particular as an app on a mobile testing device or sensor unit that can be used to implement the method. For this purpose, the testing device can be equipped with a non-volatile memory and a processor unit for interpreting and executing the commands stored in the memory.

A further aspect of the invention relates to a mobile testing device for testing an elevator system, which can be designed in particular as a cable elevator system with a rotatably mounted traction sheave. The testing device is designed in accordance with the method aspects described above to record several position values, each of which represents a position of the movable element. The position values can be recorded via sensors permanently mounted on the elevator system and/or via a sensor unit arranged on the testing device. The sensor unit can be designed according to one of the sensor devices described above.

The test device preferably also comprises an evaluation unit for determining the test parameter on the basis of the position values recorded by the sensor unit or the other sensors. One or more of the method or device aspects described above can be implemented here.

• 1 eine schematische Ansicht von Teilen einer Aufzugsanlage; und
• 2 ein schematisches Blockschaltbild von Aspekten eines Verfahrens zur Überprüfung der Treibfähigkeit einer Aufzugsanlage.

The described aspects of the invention are described below, purely by way of example, with reference to the drawings, in which:

• 1 a schematic view of parts of an elevator installation; and
• 2 a schematic block diagram of aspects of a method for checking the driving capability of an elevator system.

1 shows schematically components of a cable lift system 10 comprising a car 12 designed as a passenger cabin, which is connected to a counterweight 14 via one or more support means 16. The support means 16 can be designed as a rope or belt, for example, and is guided over a rotatably mounted traction sheave 18 and a deflection roller 20 that is also rotatably mounted. By driving the traction sheave 18 by means of an electric motor (not shown), the car 12 can be moved either vertically up or down in order to transport people or other payloads in the car 12 within the indicated elevator shaft 31 between predefined stopping positions, as is generally known in elevator systems.

Depending on the specific design of the elevator system 10, it is conceivable to dispense with the deflection pulley 20. Furthermore, it is conceivable that the drive of the elevator system 10 with the traction sheave 18 and any deflection devices is not as in 1 shown above the elevator shaft 31, but is arranged at any height of the elevator shaft 31 (e.g. in the area of any floor).

Aspects of a method for checking the traction capability of the traction sheave 18 are described below.

First, the traction sheave 18 is driven to move the elevator car 12 up or down in a vertical direction within the elevator shaft 31. To determine the position values relevant for the test, the unloaded elevator car 12 is moved upwards (in the direction away from a floor 29 of the elevator shaft 31) and decelerated to a standstill by activating the emergency stop.

During the upward movement of the elevator car 12 and the activation of the emergency stop, a large number of position values are measured, each of which indicates a measured value for the position of the elevator car 12. The position values each represent the position of the elevator car 12 within the elevator shaft 31, indicated schematically by the dashed cross arrow 30. The position values are measured at regular time intervals in order to track the spatial trajectory of the elevator car 12 until it comes to a standstill and to determine time-dependent variables such as the speed and acceleration of the elevator car 12. The position values each indicate a current vertical position of the elevator car 12 in the elevator shaft 31.

To measure the position values, a first mobile test device 24 is used, which is arranged on the roof of the elevator car 12 and has a barometric air pressure sensor. The atmospheric air pressure values measured by the air pressure sensor are converted into position values which represent the respective vertical position of the elevator car 12 within the elevator shaft 31. The air pressure values p(t) can be converted into position values x(t) by dividing by a constant k, i.e. x(t) = 1/k*p(t), where t represents the time and the constant k=Δp/h, i.e. represents the change in air pressure in relation to the change in the vertical position (height h).

In addition, a second mobile test device 28 is optionally provided, which is arranged on the underside of the counterweight 14 and records position values of the counterweight 12. The second test device 28, unlike the first test device 24, has a geomagnetic sensor. The values of the magnetic flux density B(t) measured by the geomagnetic sensor are converted into position values by dividing by the constant flux density change per position change, ie x(t) = 1/k`*B(t), where t represents the time and the constant k'=ΔB/h, ie the change of the magnetic flux density related to the change of the vertical position (height h).

The second test device 28 is connected via a wireless communication link to the first test device 24, in which all measured position values are combined.

The position values are stored and evaluated in an evaluation unit of the first test device 24, taking into account the associated time intervals between the individual measurements. In particular, the respective time-dependent acceleration values of the car 12 and the counterweight 14 during the braking process are determined from the temporally successive position values.

In addition to the position values recorded directly by the test devices 24 and 28, further measured values and constant measurement parameters are recorded. These are measured by means of sensors permanently installed on the elevator system 10 and transmitted by a control device of the elevator system 10 to the first test device 24 via a wireless communication interface (not shown). This includes the current mass of the elevator car 12 and other constant technical properties of the elevator system 10, in particular the mass of the counterweight 14, the total length and the mass of the support means 16. In addition, the length of the support means section 22, which extends between the traction sheave 18 and the elevator car 12, and the length of the support means section extending between the deflection pulley 20 and the counterweight 14 (see reference number 16) are determined.

Preferably, the lengths of these support means sections are read directly from the elevator system 10. If this is not possible for a particular elevator system, the position values recorded by means of the test devices 24 and/or 28 can be used to determine the spatial distance to the ceiling section 33. On the basis of the corresponding distance values, the support means lengths can then be calculated taking into account the fixed geometric conditions of the elevator system 10. This includes, for example, the fixed support means length between the elevator car 12 and the counterweight 14.

The measured values including the position values are processed in the test device 24 in order to obtain a reliable and accurate estimate of the traction capability of the traction sheave 18. A corresponding method is described below with reference to 2 described in more detail.

On the one hand, measured values 32 are used which are recorded directly by the test devices 24 and/or 28. These include in particular the position values. On the other hand, measured values 34 are used which are read out by the elevator system 10 as described above and transmitted to the first test device 24.

The measurement value groups 32 and 34 are first subjected to preprocessing 36 in which the measurement values are compared with predefined threshold values. A portion of the measurement values that violate one or more threshold values are excluded from further processing. On the one hand, the position values measured redundantly with the test devices 24 and 28 are compared with one another. If the deviations between individual position measurement pairs are too large, the relevant measurement values are discarded. In addition, other implausible position values are discarded, for example those that lie outside a physically possible range of motion. The measurement values are cleaned in this way. Furthermore, the measurement values 32, 34 are standardized.

In the following step 38, the measured values 32, 34 are processed with a machine-learned model that outputs the test parameter 40. The model was previously determined on the basis of a large number of training data, by specifying reference measured values that represent a desired operating behavior. Alternatively or additionally, the model can have a fixed calculation rule for the driving ability, which can be specified as follows: $$\frac{F1}{F2}=\frac{\text{G}\left(\text{G}+\ddot{\text{x}}\right)}{\text{F}\left(\text{G}-\ddot{\text{x}}\right)}$$

Here, x denotes the time-dependent distance (position change) covered by the car 12 or the support means 16 and the counterweight 14 during the predetermined operating sequence. Accordingly, ẍ denotes twice the time derivative of the distance, which corresponds to the acceleration of the car 12 or the counterweight 14. The variable G denotes the mass of the counterweight 14, the variable F the mass of the car 12 and g the acceleration due to gravity.

The test parameter 40 is calculated depending on the described values as a ratio between F1 and F2, where F1 is the load-bearing force on the side of the counterweight 14 and F2 is the load-bearing force on the side of the car 12. Optionally, the proportional load-bearing Partial masses, which vary depending on the respective route position, are added to the respective mass of the car 12 or the counterweight 14. This leads to greater accuracy because, for example, the measured mass of the car 12 also includes the mass of the support element section 22. The proportional support element masses can be determined by multiplying the proportional support element lengths by the previously known support element mass per unit length.

It is possible to determine separate position values and separate acceleration values for the car 12 and the counterweight 14, provided that the position for the car 12 and the counterweight 14 are recorded separately (using respective test devices, as described above). Alternatively, the position values can only be measured for the car 12, in which case it is assumed for the sake of simplicity that the change in position of the counterweight 14 is equal in magnitude to the change in position of the car 12 and only has an opposite sign. The acceleration values can each be determined on the basis of a difference between two successive speed values. The speed values are in turn determined from the position values.

LIST OF REFERENCE SYMBOLS

10

Elevator system

12

Car

14

Counterweight

16

Carrying means

18

Traction sheave

20

Deflection pulley

22

Suspension section

24

First test device

28

Second test device

29

Floor section

30

position

31

Elevator shaft

32

Measurement values of the test devices

33

Ceiling section

34

Measurement values of the elevator system

36

Filtering the measured values

38

Determining the test parameter

40

Test parameters

Claims (14)

Method for checking an elevator system with a rotatably mounted traction sheave, comprising: - operating the elevator system (10) according to a predefined operating sequence, wherein at least one movable element (12, 14, 16) of the elevator system (10) is moved by driving the traction sheave (18); - detecting a plurality of position values (32) while the movable element (12, 14, 16) is moved, wherein the position values each represent a spatial position of the movable element (12, 14, 16); and - determining at least one test parameter (40) on the basis of the plurality of position values, wherein the test parameter represents the driving ability of the traction sheave (18). Procedure according to Claim 1 , wherein the movable element (12, 14, 16) is formed by a first load element (12) which is connected to a second load element (14) of the elevator installation (10) via at least one support means (16), wherein the support means (16) is deflected and driven between the first load element (12) and the second load element (14) by means of the drive pulley (18) in order to move the first load element (12) and the second load element (14) simultaneously. Procedure according to Claim 2 , further comprising: - determining at least one mass of a section length (22) of the support means (16), wherein the test parameter (40) is determined as a function of the at least one determined mass. Method according to at least one of the preceding claims, wherein the movable element (12, 14, 16) is formed on a speed limiter or a shaft copy of the elevator installation (10). Method according to at least one of the preceding claims, wherein the position values are detected with at least one sensor device (24, 28), in particular a mobile sensor device, which is arranged on the movable element (12, 14, 16). Procedure according to Claim 5 , wherein the sensor device (24, 28) comprises a position sensor which determines the position of the movable element (12, 14, 16) on the basis of coded radio signals received by the position sensor, in particular wherein the radio signals are received from a global positioning system. Procedure according to Claim 5 or 6 , wherein the sensor device (24, 28) has a magnetic sensor, in particular wherein the magnetic sensor is designed as a geomagnetic sensor. Method according to one of the Claims 5 until 7 , wherein the sensor device (24, 28) has an air pressure sensor, in particular wherein the air pressure sensor is designed as a barometric pressure sensor. Method according to one of the Claims 5 until 8th , wherein the sensor device (24, 28) comprises an optical image sensor that generates image data representing at least the movable element (12, 14, 16). Method according to at least one of the preceding claims, further comprising: - detecting measured values for a measured variable that differs from the position of the movable element (12, 14, 16), and wherein the test parameter (40) is determined on the basis of the measured values. Method according to at least one of the preceding claims, further comprising: - detecting an acoustic signal at the elevator installation (10) while the movable element (12, 14, 16) is moved, and wherein the test parameter (40) is determined as a function of the acoustic signal. Method according to at least one of the preceding claims, wherein the position values and/or further measured values are recorded by means of a mobile testing device (24, 28), in particular wherein the mobile testing device (24, 28) is moved along with the movable element (12) during the recording of the position values and/or further measured values. Computer program comprising instructions which, when the program is executed by a computer, cause the computer to carry out at least one step of the method according to one of the preceding claims. Mobile testing device (24, 28) for an elevator system with a rotatably mounted traction sheave (18), comprising a sensor unit for detecting a plurality of position values for a movable element (12, 14, 16) of the elevator system (10) and an evaluation unit which is designed to determine at least one test parameter (40) which represents the driving ability of the traction sheave (18) on the basis of position values detected using the sensor unit on the elevator system (10).

Images